Fuel cells are electrochemical devices that utilize an oxidation-reduction reaction between two reactants (i.e., a reducing agent and an oxidizing agent) to convert chemical energy into electricity. In general, fuel cells are configured such that bulk reactants do not directly contact one another and electrons, which are transferred between the reactants as part of the oxidation-reduction reaction, must flow through an external circuit. This flow of electrons through the external circuit permits an electrical potential, which is generated by the oxidation-reduction reaction and produces the electron flow, to be utilized to electrically power an external device.
In contrast to batteries, which have a finite storage capacity and sometimes may be “rechargeable,” fuel cells may be referred to herein as “refillable.” As such, fuel cells generally are configured such that the reactants may be supplied to the fuel cell, replenished, and/or refilled, thereby permitting a theoretically unlimited operating time for the fuel cell. In addition, reaction products generally are removed from the fuel cell. For many prior art fuel cells, these reaction products may be gaseous, which may make it difficult to recover and/or recycle the reaction products. Thus, fuel cells may be desirable for situations in which the storage capacity of conventional batteries is insufficient to provide a desired amount of electrical power over a desired timeframe.
While many types of fuel cells have been developed, they all suffer from inherent limitations. As an example, fuel cells that utilize hydrogen gas as the reducing agent and oxygen as the oxidizing agent are known. However, because hydrogen is a gas at all but extremely low temperatures (−252.88° C. at 1 ATM), it is difficult to store in quantities sufficient to provide a significant amount of electrical power over a significant period of time. Thus, there exists a need for a fuel cell that uses reducing agents that are stored in liquid form, and that remain liquid at temperature ranges that encompass those commonly encountered on the surface of the earth, and that do not require extremely high pressures to remain liquid.